The receipt in your hand looks harmless, but its heat-sensitive coating can contain chemicals that transfer to skin, raising fresh questions about repeated everyday exposure

You pay for your groceries, collect your change and take the receipt. It is one of the most forgettable objects in everyday life, a piece of paper that may spend a few minutes in your hand before disappearing into a wallet, bag or trash can. But look closely at the printed numbers. There may not be any conventional ink on the receipt at all.

Many receipts are made from thermal paper, which contains a heat-sensitive coating. When the printer's heated head passes over the paper, it triggers a reaction between chemicals in that coating, creating the dark text and numbers. The US Environmental Protection Agency describes bisphenol A, or BPA, as one chemical that has been used as a developer in this process.

That seemingly simple printing trick has raised another question: what happens when people repeatedly handle the chemicals on these papers?

The hidden chemistry behind the print

Thermal paper generally contains a color-forming dye and a chemical called a developer. Heat from the printer causes them to react, producing the dark image that becomes the receipt.

BPA and its close relative bisphenol S (BPS) have both been used as developers. Unlike ordinary ink, these chemicals are part of the paper's surface coating rather than ink that has been printed onto it.

That matters because some of the chemicals can remain available on the surface.

A 2018 investigation by the Ecology Center's Healthy Stuff Lab tested 167 receipts collected from 148 US businesses. Researchers detected either BPA or BPS on 93% of the receipts examined: BPS appeared on 75%, while BPA appeared on 18%.

The finding did not mean that every receipt contained a dangerous amount of either substance, nor did it establish that touching one receipt causes illness. It showed instead how widespread these chemicals were in the particular sample of thermal receipts examined.

BPA was replaced, but BPS became common

As concerns about BPA grew, manufacturers increasingly moved toward alternatives.

One of the most prominent replacements has been BPS. A 2023 study published in Environmental Pollution examined 571 US receipts collected in 2022 and found BPS on 85% of them, while BPA appeared on just 1%. The researchers also detected alternatives such as Pergafast 201.

The shift is significant because replacing one chemical does not automatically settle the safety question.

The EPA's assessment of alternatives to BPA in thermal paper examined 19 potential developers and cautioned that alternatives can involve different health and environmental trade-offs. In other words, a substance being marketed as an alternative to BPA does not automatically mean it presents little concern across every possible hazard category.

Why cashiers may have a different level of exposure

For most shoppers, contact with a receipt may be brief and occasional. A cashier, however, can handle thermal paper repeatedly throughout an entire working day. That difference has been investigated.

A 2016 occupational study published in the International Archives of Occupational and Environmental Health examined BPA exposure among cashiers and other workers and investigated whether frequent handling of thermal paper was associated with increased urinary BPA levels.

Another study, published in Environmental International in 2018, followed female supermarket cashiers in South Korea. Researchers reported that urinary BPA concentrations increased after shifts among cashiers who handled receipts without gloves; the study also examined whether glove use changed exposure.

The environmental problem begins when the receipt leaves your hand

There is another reason these tiny slips of paper have attracted attention: recycling. Thermal receipts can look indistinguishable from ordinary paper, making them tempting to place in the recycling bin. But their chemical coating can introduce developers into recycled paper streams.

The Minnesota Pollution Control Agency recommends keeping thermal paper out of recycling because of concerns about BPA and BPS contamination. The scale of the waste adds another dimension.

The EcoNews article, citing estimates for the United States, reports that receipt production consumes substantial amounts of trees and water and generates hundreds of millions of pounds of waste. And all of this is for something that may be needed for only a few seconds.

The simplest way to reduce exposure and waste is also the most obvious: don't print a receipt when one is unnecessary.

Electronic receipts eliminate the need for the thermal paper itself. Where a paper receipt is required, businesses can also use thermal papers made with alternative developers.